On Friday 2 December 2011 an unknown painting by Rembrandt is being presented in the Rembrandt House. The small panel, Old Man with a Beard was painted by Rembrandt around 1630, at the end of his time in Leiden. The Rembrandt House has the painting on loan from a private collector.

The research into the painting and the attribution to Rembrandt will be explained at length during the presentation by Ernst van de Wetering (Emeritus Professor of Art History at the University of Amsterdam and head of the Rembrandt Research Project), Martin Bijl (restorer), Joris Dik (professor at the Delft University of Technology) and Koen Janssens (professor at the University of Antwerp).

Images of the painting will also be available at the presentation.

Ernst van de Wetering is convinced of the authenticity of this work on the grounds of the technical similarities in painting style to Rembrandt’s paintings dating from around 1630. There is also a copy of the painting that must have been made by one of the apprentices in Rembrandt’s studio.
The same image appears in a reproductive print of 1633, with an inscription stating that it was made by Rembrandt. Over and above this, scientific investigations have shown that there is an unfinished self-portrait by Rembrandt under the paint surface.

The self-portrait was revealed when the painting was scanned at the European Synchrotron Radiation Facility (ESRF) in Grenoble using a dual energy X-ray imaging technique, and at the Brookhaven National Laboratory (BNL) in New York using Macro-scanning X-Ray Fluorescence spectrometry (MA-XRF), a technique first applied to paintings by Professor Koen Janssens (University of Antwerp) and Professor Joris Dik (Delft University of Technology). The measurements at BNL took advantage of a newly-developed fluorescence microprobe system, which enables large area surfaces to be scanned with high definition.

XRF technology detects the pigments in hidden layers of paint, making it possible to record overpainted compositions photographically. This new technology has previously resulted in spectacular discoveries in paintings by Francisco Goya and Vincent van Gogh.

From 1 May to 1 July 2012 the Rembrandt House Museum is staging a special exhibition of research into ten paintings by Rembrandt and his contemporaries using XRF technology.

This website focuses on the scientific investigation conducted by an international consortium of scientists to visualize the hidden, unfinished self-portrait of Rembrandt hidden below the Bearded Old Man.

In the course of 2009 Ernst van de Wetering first approached Joris Dik and Koen Janssens with the present painting. Van de Wetering was reconsidering the painting's attribution at that time. One of the questions at hand concerned the potential presence of a second figure painted below the bearded Old Man. X-ray radiography and infrared reflectography had shown various alterations to the composition of the painting, notably around the collar and head dress of the figure. However, it was unclear whether the surface figure itself had been reworked or whether a second, different figure existed below the surface painting. For the art historian Ernst van de Wetering and the conservator Martin Bijl, these were important questions, relating to the paintings attribution as well as the conservation treatment.

Intrigued by these questions, Joris Dik and Koen Janssens set out an elaborate scientific campaign aiming to shed light on the painting’s enigmatic substructure.

The imaging techniques used for this investigation included X-ray radiography (XRR), dual energy (K-edge) X-ray absorption imaging and X-ray fluorescence analysis (XRF). In addition, optical and electron microscopy, combined with energy dispersive X-ray spectrometry (SEM/EDX) were used to study a microscopic paint sample, revealing the paint stratigraphy and its chemical composition.

The measurements were carried out at the Universities of Delft and Antwerp and included work at two different synchrotron radiation facilities: the European Synchrotron Radiation Facility (ESRF) in Grenoble, France and the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratories, Upton, NY, USA.

The first step was to examine the painting with K-edge absorption imaging at beam line ID17 of the ESRF. This method allows to quickly visualize the distribution of heavy elements in paintings, notably in pigments that occur in fleshtone colours such as lead white (Pb, lead) and vermillion (Hg, mercury).
However, based on the results the presence of a full-blown, second figure could be excluded. Subsequently, measurements with portable XRF spectrometry showed unusual local concentrations of copper that could not be explained by surface features in the painting. Based on these measurements made at Antwerp University, Dik and Janssens decided to perform macro-XRF elemental scanning, with the aim to chart the distribution of copper over the entire painting. Earlier, the feasibility of this technique in revealing hidden paintings had been shown on paintings by Vincent van Gogh and Francisco de Goya.

In the present case, measurements were carried out at NSLS under the guidance of Dr. Peter Siddons, providing high resolution maps of copper. The use of MAIA -- a new, fast x-ray detector developed by researchers at BNL and CSIRO -- was crucial for the visualization effort, as it allowed researchers to produce high-definition elemental maps of the entire painting.

The copper distribution revealed the contour lines of a beardless, seemingly younger male figure wearing a beret. This distribution image corresponds to the initial sketch of the painting, also known as the underpainting. Cross-sectional analysis later on confirmed the presence of copper in the lower layer of the paint stratigraphy. Apparently, this first version of the painting had not been completed, but was abandoned in favour of the present surface figure.

It was in the contours of this unfinished figure that Ernst van de Wetering recognized the typical posture, hair dress, white collar and black beret that characterizes many of the (early) self-portraits of Rembrandt. Based on this analogy, he concluded that the painting had been started as a self-portrait, left unfinished and then changed into the present Bearded Old Man.

In combination with other arguments of art historical nature, the investigation with synchrotron X-rays proved to be a crucial piece of evidence in finally attributing the painting to Rembrandt.

Step 1 (Amsterdam, NL)

Photograph ((c) R. Gerritsen) of 'Old man with a beard', before restauration.

(Click on the image to view a larger version.)

Conventional X-ray radiography ((c) R. Gerritsen) of the painting shows that below the 'Old man with a beard', another representation may be present.

Close-up of the painting at beamline ID17 of the European Synchrotron Radiation Facility (Grenoble, France)

(Click on the image to view a larger version.)

Dual energy X-ray radiograph obtained at ESRF ID17, reflecting the distribution of Pb in the painting.

In contrast to the conventional X-ray radiograph, the structure of the wood panel no longer dominates this image. Thus, the collar and general posture of the person in the overpainted portrait is more clearly visible. However, the general shape of the head of the person and any details of the face remain invisible.

(Click on the image to view a larger version.)

Aerial view of the ESRF, Grenoble, France (credit: ESRF/A. Petricola)

(Click on the image to view a larger version.)

Step 3: PXRF investigations, Antwerp, B

Locations on the painting where the local composition was determined by means of PXRF (Portable X-ray fluorescence analysis).

On positions 8-12 and 17, an increased level of Copper (Cu) was observed.

Examination of a paint sample by optical and electron microscopy, collected from the background (copper rich) part of the painting reveals coarse blueish pigment particles (see arrow), rich in Copper, to be present in the darker lower layer.

K. Janssens is grateful for the support from FWO, Brussels through projects G.0704.08
and G.01769.09 and their "Big Science" programme.
J. Dik acknowledges the support from NWO, Den Haag through their VIDI programme.

Detector R&D at Brookhaven National Laboratory is supported by the U.S. Department of Energy.